Method for determining, without physical contact, the swivel position of a body clamped into a rotary support

ABSTRACT

Apparatus for determining the swivel position of a body which is clamped into a rotary support rotating about a rotational axis and which is swiveled about a swivel axis that is angularly offset in relation to the rotational axis, and doing so without relying on physical contact. One or more transmitter element is supported on a rotary support and is swingable with the body eccentrically about the swivel axis. One or more scanning probe is disposed in a fixed position adjacent the rotary support, so that the transmitter element is moved past it without touching it when the support rotates. An interpretive device is controlled by the scanning probe and evaluates the offset of the transmitter element in relation to the scanning probe caused by the swiveling of the transmitter element, thereby determining the swivel position of the body.

United States Patent 1191 Junike et al.

1 1 June 5,1973

, [541' METHOD FOR DETERMINING,

WITHOUT PHYSICAL CONTACT, THE SWIVEL POSITION OF A BODY CLAMPED INTO AROTARY SUPPORT [73] Assignee: Werkzeugmaschinenfabrlk Gildemeister &Comp. AG, Bielefeld, Germany [221 Filed: Nov.3, 1971 211 Appl. No.:195,325

[30] Foreign Application Priority Data May 4, 1971 Germany ..P 21 22051.9

52- u.s. c1 ..3l8/602, 318/467 [51] Int. Cl..... ..G05b 19/28 [581 Fieldof Search ..'....3l8/602, 673, 601, 318/466-470 [56] I References CitedUNITED STATES PATENTS 3,104,351 9/1963 Rosenberg ..318/602 11/1965Pricem. ..-...318/60-l 6/1972 Crosby ..3l8/602 Primary Examiner-BemardA. Gilheany. Assistant Examiner-Thomas Langer Attorney Owen, Wickersham& Erickson [5 7 ABSTRACT Apparatus for determining the swivel positionof a body which is clamped into a rotary support rotating about arotational axis and which is swiveled about a swivel axis that isangularly offset in relation to the rotational axis, and doing sowithout relying on physical contact. One or more transmitter element issupported on a rotary support and is swingable with the bodyeccentrically about the swivel axis. One or more scanning probe isdisposed in a fixed position adjacent the rotary support, so that thetransmitter element is moved past it without touching it when thesupport rotates. An interpretive device is controlled by the scanningprobe and evaluates the offset of the transmitter element in relation tothe scanning probe caused by the swiveling ofthe transmitter element,

thereby determining the swivel position of the body.

8 Claims, 7 Drawing Figures v PATENTEDJUN Elm 3,737,153

' SHEET 1 0F 2 Q INVENTOR WILHELM AUGUST KARL JUNlKE THEODOR FRANZ HA UK UM,MM "W ATTORNEYS PATENTEDJUN 5197s 737, 753

SHEET 2 BF 2 ROTARY DRIVE FIG-.4

LOGIC CIRCUIT.

INVENTOR WILHELM GLST KARL JUNIKE A THEODOR I; fly UC 4 MMQQL,

ATTORNEYS METHOD FOR DETERMINING, WITHOUT PHYSICAL CONTACT, THE SWIVELPOSITION OF A BODY CLAMPED INTO A ROTARY SUPPORT BACKGROUND OF THEINVENTION The invention relates to an apparatus for determining theswivel position of a body which is clamped into a support that isrotatingabout a rotational axis, the body being swiveled in the supportabout a swivel axis which is angularly offset in relation to therotational axis.

The rotary support may, for example, be a hollow rotating chuck for aworkpiece that is to be machined by a rotary machine, such as a lathe.In order that the workpiece can be machined from several sides, thechuck may be provided with a plurality of inwardly projecting grippingjaws for the workpiece, the gripping jaws swiveling about a swivel axisthat extends perpendicularly to the rotational axis of the chuck. Anexample of a workpiece that must be machined from several sides is, forexample, a valve housing having a plurality of radial sockets or flangeswhich are to be machined in the rotary machine. If thesockets are offsetfrom each other in 90increments, the valve body must be moved in thechuckby 90 in order that the next socket may be brought into theprescribed operational position.

As a rule, the workpiece is swiveled in the chuck by a pivot driveprovided on the chuck. The pivot drive may swivel the workpiece withoutits being necessary to interrupt the rotation of the chuck. Heretofore,the swivel position of the workpiece has been determined by mechanicaldevices which came into contact with the chuck or workpiece. However,this method has proved unsatisfactory, particularly since the contactingparts became worn in the course of time.

An important object of the invention is therefore to determine theswivel position of a body clamped into a rotary support rotating about arotational axis and to do so without involving physical contact.

SUMMARY OF THE INVENTION The apparatus of this invention ischaracterized by (l) at least one transmitter element provided on therotary support and swiveling together with the body eccentrically aboutthe swivel axis, (2) at least one scanning probe fixedly disposedadjacent the support, and past which the transmitter element is movedwhile leaving a clearance between the support and the transmitterelement, and (3) an analyzing device controlled by the scanning probefor analyzing the offset of the transmitter element in relation to thescanning probe, as produced by the rotation of the transmitter element,to determine the rotational position of the body.

A plurality of scanning probes is preferably provided and disposed sothat, with each predetermined swivel position of the body, thetransmitter is moved past one of the scanning probes.

To increase the possibilities of variation in the selection ofrotational positions, a plurality of transmitters may be provided at avariable distance from the swivel axis of the rotary support and offsetby a predetermined swivel angle, the scanning probes being disposed sothat at least one transmitter is moved past a scanning probe in eachpredetermined swivel position of the body. v

The scanning probes may be, for example, proximity switches, and thetransmitters for actuating the proximwith two inwardly projectingclamping jaws which swivel about the swivel axis and serve for grippinga workpiece to be machined, the transmitters may be dis- I posed on theoutwardly pointing face of a plate connected to one of the clamping jawsand swiveling about the swivel axis.

In a further suitable development, the analyzing device may comprise aselector unit for selecting the desired swivel position of the body aswell as an interpretive logic controlling a swivel drive on the rotarysupport, so that the swivel drive is switched on when the interpretivelogic senses an undesired swivel position, and is switched off when theinterpretive logic senses the desired swivel position.

It is possible for errors in measuring to occur due to chips flying pastthe scanning probes. It is therefore advisable to construct theinterpretive logic so that, of two control pulses fed to the logic bythe scanning probes at any time whose chronological interval falls shortof a minimum interval, only the last pulse is. analyzed and the reactionproduced by the first pulse is corrected.

Other objects and advantages of the invention will appear from thefollowing description of a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS I chuck into which a workpiece isswingably clamped, in

combination a device for determining the swivel position of theworkpiece, without making physical contact with the workpiece or thechuck.

FIG. 2 is a view in perspective of the workpiece which in FIG. 1 isclamped into the chuck.

FIG. 3 is another view in perspective of the same workpiece, viewed fromanother angle.

FIG. 4 is a schematic representation and block diagram of the device ofFIG. 1 for determining the swivel position of the workpiece, withoutmaking physical contact.

FIG. 5 is a similar view of a portion of FIG. 4, with the parts in adifferent position.

FIG. 6 is a view similar to FIG. 5, with parts shown in a thirdposition.

FIG. 7 is another view similar to FIG. 5 with the parts in a fourthposition.

DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 1 shows a lathe l of a rotarymachine with a hollow chuck 2 secured thereon. The chuck 2 is providedwith two clamping jaws 3 and 4; these jaws 3 and 4 project into theinterior of the chuck 2 from diametrically opposite sides, and both ofthem are swiveled about a swivel axis 7, as by means by a pivot drive(not shown). The lathe l, the chuck 2 and the clamping jaws 3 and 4rotate together as an assembly about a rotational axis 5.

A workpiece 6 is firmly clamped between the jaws 3 and 4. The workpiece6, shown in greater detail in FIGS. 3 and 4, is illustrated by way ofexample as a valve housing which has four sockets 20, 21, 22, and 23offset by 90 and disposed in one plane. The valve housing 6 is clampedbetween the jaws 3 and 4 so that the plane in which the sockets 20, 21,22, and 23 are disposed extends perpendicularly to the swivel axis 7.

After each swiveling motion of the workpiece by 90, another socket isbrought into operational position. The chuck 2 may, for example, formpart of a rotary machine which is to give the sockets a finishingturning.

To enable determination of the swivel position of the workpiece 6 in thechuck 2, a plate 10 is provided on the outside of the chuck 2 and isconnected with the jaw 4.'On its outwardly directed face, the plate 10carries two trip cams 11 which are eccentrically offset by 90 inrelation to the swivel axis 7. When the workpiece 6 is swiveled by thejaw 4, the plate 10 is also swiveled by the jaw 4.

Adjacent to the chuck 2, and spaced from it, is provided a fixedmeasuring head 8 containing four scanning probes 9. The four scanningprobes 9 are arranged in a row parallel to the rotational axis of thechuck 2. The scanning probes 9 are proximity switches, each of which isactuated when one of the trip cams 11 reaches a certain proximity, inthis instance underneath and in alignment with the switch. The switches9 are disposed so that a clearance always exists between them and thetrip cams 11. This insures scanning without any need of physicalcontact.

In FIGS. 4-7, the operational principle of the apparatus for scanningwithout relying on physical contact is schematically represented. Thetwo trigger earns 11 on the plate 10 are designated. A and B. The fourproximity switches 9 are designated a, b, c and d. The switches 9 aredisposed so that in each of the four swivel positions of the workpiece6, which are offset by 90 in relation to each other, one of the triggercams 11 passes with a predetermined clearance relative to and underneathone of the proximity switches 9.

The desired swivel positions are adjusted on a selector unit 12 providedwith four selector switches 13 corresponding to the four approximationswitches 9. The selector switches 13 are designated a, b, c and d. Aninterpretive logic l4 examines whether the swivel position establishedby the measuring head 8 coincides with the swivel position adjusted onthe selector unit 12. If there is no coincidence, then the interpretivelogic 14 turns on the swivel or pivot drive 15, thus causing furtherswiveling of the workpiece 6. The workpiece 6 is swiveled so long untilthe correct swivel position has been established.

From the four swivel positions illustrated in FIGS. 4-7 it will be seenthat, with each rotation of the plate 10 by 90, one of the two triggercams 11 passes underneath and in line with one of the proximity switches9.

By modifying the number and arrangement of the proximity switches andthe trigger cams, a multiplicity of swivel positions or angularpositions is obtained.

To those skilled in the art to which this invention relates, manychanges in construction and widely differing embodiments andapplications of the invention will suggest themselves without departingfrom the spirit and scope of the invention. The disclosures and thedescription herein are purely illustrative and are not intended to be inany sense limiting.

We claim:

1. Apparatus for determining the swivel position of a body which is heldin a rotary support rotating about a rotational axis by clamps which areswiveled in said rotary support to rotate about a swivel axis which isangularly offset in relation to said rotational axis, comprising:

at least one transmitter element mounted on one said clamp eccentric tosaid swivel axis and thereby swiveling with said body but eccentricallyabout said swivel axis, at least one scanning probe disposed in a fixedposition adjacent said rotary support and past which said transmitterelement is moved by rotation of said rotary support with a clearance atall times between said scanning probe and said transmitter element, and

interpreting means controlled by said scanning probe for evaluating theoffset of said transmitter element in relation to said scanning probe asoffset is caused by swiveling of said transmitter element when said bodyand said clamps swivel relative to said rotary support, therebydetermining the swivel position of said body.

2. Apparatus in accordance with claim 1, wherein a plurality of scanningprobes is provided, each at a different fixed position, said probesbeing so disposed in their positions that, with each of a series ofpredetermined swivel positions of said body said transmitter element ismoved past one and only one said scanning probe.

3. Apparatus in accordance with claim 2, characterized in that aplurality of transmitter elements is provided, each mounted on one saidclamp and each lying at a different distance from said swivel axis, saidtransmitter elements being offset from each other by a predeterminedswivel angle, said scanning probes being so disposed that, with eachsaid predetermined swivel position of said body, at least onetransmitter is moved past one said scanning probe.

4. Apparatus in accordance with claim 2 wherein said scanning probes aredisposed in a row parallel to the rotational axis of said support.

5. Apparatus in accordance with claim 2, wherein the scanning probes areassembled in a measuring head.

6. Apparatus in accordance with claim 2 wherein said interpretive meanscomprises a selector unit for selecting a plurality of desiredpredetermined swivel positions of said body, an interpretive logiccircuit, and a swivel drive on said rotary support controlled by saidlogic circuit so that said swivel drive is turned on when theinterpretive logic circuit senses an undesired swivel position, and saidswivel drive is turned off when said interpretive logic circuit senses adesired swivel position.

7. Apparatus in accordance with claim 1, characterized in that eachscanning probe is a proximity switch, and each transmitter element is atrigger cam suitable for actuating said proximity switch. I

8. Apparatus in accordance with claim 1, wherein said rotary support isa chuck with two inwardly projecting clamping jaws swiveling about theswivel axis and comprising said clamps, for holding said body as aworkpiece, at least one said jaw having a plate connected to itsradially outer face, each said transmitter element being mounted on asaid plate and comprising a trigger cam mounted on said plateeccentrically mounted with respect to said swivel axis.

* k l l

1. Apparatus for determining the swivel position of a body which is heldin a rotary support rotating about a rotational axis by clamps which areswiveled in said rotary support to rotate about a swivel axis which isangularly offset in relation to said rotational axis, comprising: atleast one transmitter element mounted on one said clamp eccentric tosaid swivel axis and thereby swiveling with said body but eccentricallyabout said swivel axis, at least one scanning probe disposed in a fixedposition adjacent said rotary support and past which said transmitterelement is moved by rotation of said rotary support with a clearance Atall times between said scanning probe and said transmitter element, andinterpreting means controlled by said scanning probe for evaluating theoffset of said transmitter element in relation to said scanning probe asoffset is caused by swiveling of said transmitter element when said bodyand said clamps swivel relative to said rotary support, therebydetermining the swivel position of said body.
 2. Apparatus in accordancewith claim 1, wherein a plurality of scanning probes is provided, eachat a different fixed position, said probes being so disposed in theirpositions that, with each of a series of predetermined swivel positionsof said body said transmitter element is moved past one and only onesaid scanning probe.
 3. Apparatus in accordance with claim 2,characterized in that a plurality of transmitter elements is provided,each mounted on one said clamp and each lying at a different distancefrom said swivel axis, said transmitter elements being offset from eachother by a predetermined swivel angle, said scanning probes being sodisposed that, with each said predetermined swivel position of saidbody, at least one transmitter is moved past one said scanning probe. 4.Apparatus in accordance with claim 2 wherein said scanning probes aredisposed in a row parallel to the rotational axis of said support. 5.Apparatus in accordance with claim 2, wherein the scanning probes areassembled in a measuring head.
 6. Apparatus in accordance with claim 2wherein said interpretive means comprises a selector unit for selectinga plurality of desired predetermined swivel positions of said body, aninterpretive logic circuit, and a swivel drive on said rotary supportcontrolled by said logic circuit so that said swivel drive is turned onwhen the interpretive logic circuit senses an undesired swivel position,and said swivel drive is turned off when said interpretive logic circuitsenses a desired swivel position.
 7. Apparatus in accordance with claim1, characterized in that each scanning probe is a proximity switch, andeach transmitter element is a trigger cam suitable for actuating saidproximity switch.
 8. Apparatus in accordance with claim 1, wherein saidrotary support is a chuck with two inwardly projecting clamping jawsswiveling about the swivel axis and comprising said clamps, for holdingsaid body as a workpiece, at least one said jaw having a plate connectedto its radially outer face, each said transmitter element being mountedon a said plate and comprising a trigger cam mounted on said plateeccentrically mounted with respect to said swivel axis.